1. Field of the Invention
The present invention relates to a liquid-cooled permanent chill mold for the continuous casting of metals.
2. Description of Related Art
It is within the related art to rough-work permanent chill mold plates from massive copper blocks, especially if the permanent chill mold plate is to be a component of a broad face plate in a beam blank mold. A beam blank mold is used for producing a preliminary I-profile by casting technique, which after casting is to be processed further by rolling technology. The casting surface geometry and also the cooling channel geometry are produced by cutting operations on the copper blocks. The permanent chill mold plates have very thick walls. Based on this construction principle and production principle, the possibilities are limited for shaping the cooling gap geometry according to requirements. Furthermore, thermal expansions of the regions close to the casting surfaces, which are created as a result of heat inputs by the metal melt, are impeded based on the thick-walled, and therefore stiff execution of the permanent chill mold plate, which increases the operating stress in the regions close to the casting surfaces.
In view of the fact that the copper permanent chill mold plate has been developed to be thick-walled up to now, as a rule, the fastening bolts for connecting the permanent chill mold plate to the adapter plate being typically selected to be greater than M 16, there has been no problem with maintaining greater distances between the fastening bolts. During the course of the transition to thin-walled permanent chill mold plates, because of the limited depth of screwing in the fastening bolts, one is only able to work now with fastening bolts that are smaller than, or equal to M 16. As a result of the stresses on the permanent chill mold plate during continuous casting, in the form of thermal expansions, cooling water pressure, clamping forces, the strain between the permanent chill mold plate and the adapter plate, as well as the limited space for fastening the permanent chill mold plate on the adapter plate, there is created, particularly in the top and base regions of the broad face plate, the problem of assuring a mold-strength fixing of the thin-walled permanent chill mold plate.
The conventional strain of the permanent chill mold plate and the adapter plate using fastening bolts is also disruptive based on the necessary sealing of the permanent chill mold plate from the adapter plate, since a seal has to be put around the fastening bolts. Besides that, fastening bolts situated in the edge region lead to additional uncooled, or rather poorly cooled regions of the permanent chill mold plate. Finally, in the case of a beam blank mold, an additional difficulty is the special geometry of a broad face plate in the area of the rounded transitions between the legs and the middle crosspiece on the one hand, and the legs and the flanges at the edge on the other hand. At this point, high pressure forces have to be transferred without, however, having enough space for a sufficient number of fastening bolts.